I'm going to shut down the nodemon server, use clear, and we can run git status to see what kind of changes we have:

Here we just have two files. They're modified, which means we can use git commit with the -am flag, whether it's separate or the same they have identical feature sets, and then we provide our message string, Send messages to only people in same room:

git commit -am 'Send messages to only people in same room'

With this in place we can go ahead and use git push to push this up to GitHub, and I'm also going to go ahead and deploy to Heroku using git push heroku master. Once it's deployed on Heroku, we can take just a quick moment to make sure all of those features we just added are still working as expected. I expect they will still work but it's definitely worth checking out because the environments are a little different and there's always a chance something can go wrong.

Now if something does go wrong, as a reminder you can always use heroku logs, this is going to show you the logs on the server, it's usually kind of cryptic but when an error occurs you're going to see a really big block. It's usually pretty easy to spot and it usually contains useful information as to what went wrong:

It looks like our app deployed successfully, so I can use heroku open to open it up inside my browser, and once it's open we can actually visit some chat rooms. I'm going to close down my localhost tab and I'm going to join as Andrew, the room Philadelphia:

Once I'm in the room, I am going to send a message, and then I'm going to add a second user to the room. We want to visit our Heroku app website. I'm going to visit that, we'll join the room as Vikram, and we can join the exact same room Philadelphia. When I join, I see the People list updates for both and sending messages does still work:

Messages from the second tab do appear in first tab, this is great. All this is possible because we wired up server.js, keeping track of users over time. When they first join we add them to the list, when they send messages we make sure to use their information, and when they leave we remove them from the list. This ensures that the People list is always up to date and that messages are only getting sent to others in the same room.